Biochips including a microarray comprising a two-dimensional grid of biosensors provide miniaturized laboratories that can perform a large number (e.g., hundreds or thousands) of simultaneous biochemical reactions. Biochips enable researchers to quickly screen large numbers of biological analytes for a variety of purposes.
The two-dimensional grid of biosensors of the microarray is an important component of a biochip. Conventionally, the biosensors are deposited on a flat substrate (e.g., chip), which may either be passive (e.g., silicon or a glass) or active, where “active” refers to the inclusion of integrated electronics and/or micromechanical devices that perform or assist in signal transduction.
Surface chemistry is typically used to covalently bind sensor molecules to the substrate. The fabrication of microarrays is generally challenging and is recognized as a major economic and technological hurdle. A significant manufacturing challenge is the process of placing each sensor at a specific position on the substrate. Various methods exist to provide sensor placement, including robotic micro-pipetting to place tiny spots of sensor (e.g., receptor) material on the substrate surface. Because each sensor is generally unique, only a few spots can be placed at a time. The low-throughput nature of this placement process results in high manufacturing costs.